1. Field of the Invention
The present invention relates to internal combustion engine pistons and more particularly relates to pistons which lubricate as well as maintain compression within the engine.
2. General Background of the Invention
In the field of combustion engines, pistons are normally provided with a pair of compression rings around the outer portion of the piston and substantially near the top thereof for maintaining compression within the cylinder by continued contact of the compression rings with the cylinder wall. However, pistons have not been utilized which lubricate the cylinder wall and maintain compression within the cylinder at the same time. A variety of lubricating devices are disclosed in the art which utilize pistons and lubricants in combination but do not disclose use of the lubricant as a means for retaining compression in the cylinder with the piston.
U.S. Pat. No. 415,097, issued to F. Devlin, entitled "Piston Packing," illustrates a lubricating bore through the piston rod and a lateral bore through the piston head to provide lubrication in the area of the piston head. The object of the invention is to carry water or other lubricant between two sets of rings in a metallic steam packing.
U.S. Pat. No. 648,153, issued to J. P. Serve, entitled "Means For Lubricating Engine Cylinders," teaches the use of a bore within the piston rod up to the piston head with the lubricant exiting in the body of the piston against the wall of the cylidner. This invention is utilized for lubrication and also provides a means for draining off the excess lubricant which may accumulate.
U.S. Pat. No. 2,188,105, issued to W. T. Caldwell, entitled "Lubricating Mechanism For Reciprocating Pumps And Similar Devices," shows the use of a bore within the piston rod which communicates with a lateral bore in the piston for lubricating the space between the piston and the cylinder wall. This invention addresses the problem of lubrication and preventing debris from getting between the piston and the cylinder wall but is used as a pump and not as a cylinder would be used in an internal combustion engine for maintaining compression.
U.S. Pat. No. 2,268,544, issued to C. J. Coberly, entitled "Lubricated Piston," illustrates the use of a bore within the piston rod and head for providing lubrication between the piston head and the cylinder wall to permit a flow of lubricant to the sliding surfaces of the piston and the liner so as to lubricate them and prevent foreign materials from lodging therebetween.
U.S. Pat. No. 2,748,718, issued to J. W. MacClatchie, entitled "Pump And Piston Combination," teaches the use of a bore within the piston rod communicating with a bore in the piston for lubricating the wall between the piston and the cylinder wall. The patent does not discuss use of the lubricant as a means for retaining compression.
French Pat. No. 998,327, shows the use of lubrication between the piston and wall of the cylinder.
U.S. Pat. Nos. 832,956; 2,295,160; and 2,366,832 are pertinent only in that they teach means of lubrication.